diff --git a/types/firefox-webext-browser/index.d.ts b/types/firefox-webext-browser/index.d.ts
index d9e9e8df7c..3a0bbc6a4c 100644
--- a/types/firefox-webext-browser/index.d.ts
+++ b/types/firefox-webext-browser/index.d.ts
@@ -6915,7 +6915,7 @@ declare namespace browser.tabs {
 
     type _TabsOnUpdatedEvent<T = (tabId: number, changeInfo: {
         /** The tab's new attention state. */
-        attention: boolean;
+        attention?: boolean;
         /** The tab's new audible state. */
         audible?: boolean;
         /** True while the tab is not loaded with content. */